Students should often be allowed to work in groups, ______ gives them chances to co-operate and to share.

A. who　　　　 B. where　　 　　　 C. which　　 　　　　　 D. what

Students should often be allowed to work in groups       gives them chances to co-operate and to share．

    A．who                    B．where                  C．which                    D．what